Degrees of Freedom of MIMO Two-Way X Relay Channel
Wireless communication has been advancing at an exponential rate, due to the increasing expectations for multimedia services. Among those factors limiting the capacity of wireless networks, interference has been seen as a key bottleneck. Recently, two novel signaling schemes have been proposed to deal with the interference problem: interference alignment and network coding. In this paper, the authors study the degrees of freedom of a Multiple-Input Multiple-Output (MIMO) two-way X relay channel, i.e., a system with two groups of source nodes and one relay node, where each of the two source nodes in one group wants to exchange independent messages with both the two source nodes in the other group via the relay node.